Intermediate Level Of Complexity Research Articles

Musicians and non-musicians show different preference profiles for single chords of varying harmonic complexity.

The inverted U hypothesis in music predicts that listeners prefer intermediate levels of complexity. However, the shape of the liking response to harmonic complexity and the effect of musicianship remains unclear. Here, we tested whether the relationship between liking and harmonic complexity in single chords shows an inverted U shape and whether this U shape is different for musicians and non-musicians. We recorded these groups' liking ratings for four levels of harmonic complexity, indexed by their level of acoustic roughness, as well as several measures of inter-individual difference. Results showed that there is an inverted U-shaped relationship between harmonic complexity and liking in both musicians and non-musicians, but that the shape of the U is different for the two groups. Non-musicians' U is more left-skewed, with peak liking for low harmonic complexity, while musicians' U is more right-skewed, with highest ratings for medium and low complexity. Furthermore, musicians who showed greater liking for medium compared to low complexity chords reported higher levels of active musical engagement and higher levels of openness to experience. This suggests that a combination of practical musical experience and personality is reflected in musicians' inverted U-shaped preference response to harmonic complexity in chords.

Trust, Transparency, and Complexity

AbstractThis paper develops a theory that generates an equilibrium relationship between product complexity, transparency, and trust in firms. Complexity, transparency, and the evolution of trust are all endogenous, and equilibrium transparency is nonmonotonic. The least-trusted firms choose the lowest product complexity, remain opaque, and substitute ex ante third-party verification for information disclosure and trust. Firms with an intermediate level of trust choose an intermediate level of complexity and transparency through disclosure, with more trusted firms choosing greater complexity and lower transparency. The most-trusted firms choose maximum complexity while remaining opaque, eschewing both verification and disclosure.

UniFHy v0.1.1: a community modelling framework for the terrestrial water cycle in Python

Abstract. The land surface, hydrological, and groundwater modelling communities all have expertise in simulating the hydrological processes at play in the terrestrial component of the Earth system. However, these communities, and the wider Earth system modelling community, have largely remained distinct with limited collaboration between disciplines, hindering progress in the representation of hydrological processes in the land component of Earth system models (ESMs). In order to address key societal questions regarding the future availability of water resources and the intensity of extreme events such as floods and droughts in a changing climate, these communities must come together and build on the strengths of one another to produce next-generation land system models that are able to adequately simulate the terrestrial water cycle under change. The development of a common modelling infrastructure can contribute to stimulating cross-fertilisation by structuring and standardising the interactions. This paper presents such an infrastructure, a land system framework, which targets an intermediate level of complexity and constrains interfaces between components (and communities) and, in doing so, aims to facilitate an easier pipeline between the development of (sub-)community models and their integration, both for standalone use and for use in ESMs. This paper first outlines the conceptual design and technical capabilities of the framework; thereafter, its usage and useful characteristics are demonstrated through case studies. The main innovations presented here are (1) the interfacing constraints themselves; (2) the implementation in Python (the Unified Framework for Hydrology, unifhy); and (3) the demonstration of standalone use cases using the framework. The existing framework does not yet meet all our goals, in particular, of directly supporting integration into larger ESMs, so we conclude with the remaining limitations of the current framework and necessary future developments.

Hamilton’s rule, the evolution of behavior rules and the wizardry of control theory

This paper formalizes selection on a quantitative trait affecting the evolution of behavior (or development) rules through which individuals act and react with their surroundings. Combining Hamilton’s marginal rule for selection on scalar traits and concepts from optimal control theory, a necessary first-order condition for the evolutionary stability of the trait in a group-structured population is derived. The model, which is of intermediate level of complexity, fills a gap between the formalization of selection on evolving traits that are directly conceived as actions (no phenotypic plasticity) and selection on evolving traits that are conceived as strategies or function valued actions (complete phenotypic plasticity). By conceptualizing individuals as open deterministic dynamical systems expressing incomplete phenotypic plasticity, the model captures selection on a large class of phenotypic expression mechanisms, including developmental pathways and learning under life-history trade-offs. As an illustration of the results, a first-order condition for the evolutionary stability of behavior response rules from the social evolution literature is re-derived, strengthened, and generalized. All results of the paper also generalize directly to selection on multidimensional quantitative traits affecting behavior rule evolution, thereby covering neural and gene network evolution.

The Advances in Glioblastoma On-a-Chip for Therapy Approaches.

Simple SummaryThis systematic review showed different therapeutic approaches to glioblastoma on-a-chip with varying levels of complexity, answering, from the simplest question to the most sophisticated questions, in a biological system integrated in an efficient way. With advances in manufacturing protocols, soft lithography in PDMS material was the most used in the studies, applying different strategy geometrics in device construction. The microenvironment showed the relevant elaborations in co-culture between mainly human tumor cells and support cells involved in the collagen type I matrix; remaining an adequate way to assess the therapeutic approach. The most complex devices showed efficient intersection between different systems, allowing in vitro studies with major human genetic similarity, reproducibility, and low cost, on a highly customizable platform.This systematic review aimed to verify the use of microfluidic devices in the process of implementing and evaluating the effectiveness of therapeutic approaches in glioblastoma on-a-chip, providing a broad view of advances to date in the use of this technology and their perspectives. We searched studies with the variations of the keywords “Glioblastoma”, “microfluidic devices”, “organ-on-a-chip” and “therapy” of the last ten years in PubMed and Scopus databases. Of 446 articles identified, only 22 articles were selected for analysis according to the inclusion and exclusion criteria. The microfluidic devices were mainly produced by soft lithography technology, using the PDMS material (72%). In the microenvironment, the main extracellular matrix used was collagen type I. Most studies used U87-MG glioblastoma cells from humans and 31.8% were co-cultivated with HUVEC, hCMEC/D3, and astrocytes. Chemotherapy was the majority of therapeutic approaches, assessing mainly the cellular viability and proliferation. Furthermore, some alternative therapies were reported in a few studies (22.6%). This study identified a diversity of glioblastoma on-a-chip to assess therapeutic approaches, often using intermediate levels of complexity. The most advanced level implemented the intersection between different biological systems (liver–brain or intestine–liver–brain), BBB model, allowing in vitro studies with greater human genetic similarity, reproducibility, and low cost, in a highly customizable platform.

An investigation of the lexico-grammatical profile of English legal- lay language

The article presents a study on the lexico-grammar of the genre ofEnglish legal-lay language (Tiersma 1999), using the English subcorpus of theCorIELLS corpus (Busso forthcoming). The study explores four grammaticalconstructions (in Goldberg 2006’s Construction Grammar sense): nominalisationsheading prepositional phrase attachments, modal verb constructions, participialreduced relative constructions, and passive constructions. Specifically, we usecollostructional analysis (Stefanowitsch 2013), followed by a vocabulary analysisusing English core vocabulary as a reference (Brezina and Gablasova 2015), anda comparative frequency analysis with corpora of legal language and general-domain written prose. Results of this first part of the study foreground how legal-lay language is quantitatively different from both neighbouring genres, suggestingthat it might be considered a “blended” genre. We further explore the data in termsof accessibility for speakers, using readability metrics and a survey on Englishparticipants. Both methods show that legal-lay language is at an intermediatelevel of complexity between legal jargon and general-domain prose; however, wefurther note that readability metrics generally underestimate speakers’ ability tocomprehend legal-lay language.

Reynolds and Weissenberg numbers in viscoelastic flows

One of the greatest challenges in performing numerical simulations of viscoelastic flow is how to choose the model parameters in order to be able to achieve quantitative agreement with experimental measurements in benchmark geometries. In the present work, we revisit the original concepts of Reynolds (Re) and Weissenberg (Wi) numbers in order to provide means to adequately choose those parameters. In particular, we highlight the importance of the Oldroyd-B model as a reference for viscoelastic behavior and propose a new methodology for the comparison between general viscoelastic models and the Oldroyd-B model. We identify inconsistencies in the usual approach consensually adopted in the literature. The historical reason for that seems to have its root on the fact that Reynolds and Weissenberg numbers are recognized as expressions and not as concepts. This paradigm allows the choice of parameters of a model as characteristic quantities. We propose here to choose the Oldroyd-B model parameters for the comparison with more complex viscoelastic models so that Re and Wi concepts are maintained. To illustrate this matter, we simulate a flow which is known for capturing an important viscoelastic effect, the transient extrudate swell problem. We tested three viscoelastic models with intermediate levels of complexity, namely PTT, Giesekus, and FENE-P. The traditional and the proposed approaches are compared and the role of the extra parameter, that endows these models with a nonlinear character with respect to the stress, is reinterpreted. It is demonstrated that the nonlinearity introduced by this extra parameter is overestimated in the usual formulation.

Constrained proteome allocation affects coexistence in models of competitive microbial communities

Microbial communities are ubiquitous and play crucial roles in many natural processes. Despite their importance for the environment, industry and human health, there are still many aspects of microbial community dynamics that we do not understand quantitatively. Recent experiments have shown that the structure and composition of microbial communities are intertwined with the metabolism of the species that inhabit them, suggesting that properties at the intracellular level such as the allocation of cellular proteomic resources must be taken into account when describing microbial communities with a population dynamics approach. In this work, we reconsider one of the theoretical frameworks most commonly used to model population dynamics in competitive ecosystems, MacArthur’s consumer-resource model, in light of experimental evidence showing how proteome allocation affects microbial growth. This new framework allows us to describe community dynamics at an intermediate level of complexity between classical consumer-resource models and biochemical models of microbial metabolism, accounting for temporally-varying proteome allocation subject to constraints on growth and protein synthesis in the presence of multiple resources, while preserving analytical insight into the dynamics of the system. We first show with a simple experiment that proteome allocation needs to be accounted for to properly understand the dynamics of even the simplest microbial community, i.e. two bacterial strains competing for one common resource. Then, we study our consumer-proteome-resource model analytically and numerically to determine the conditions that allow multiple species to coexist in systems with arbitrary numbers of species and resources.

Where do you think you’re going? Accounting for ontogenetic and climate‐induced movement in spatially stratified integrated population assessment models

AbstractUnderstanding spatial population structure and biocomplexity is critical for determining a species’ resilience to environmental and anthropogenic perturbations. However, integrated population models (IPMs) used to develop management advice for harvested populations have been slow to incorporate spatial dynamics. Therefore, limited research has been devoted to understanding the reliability of movement parameter estimation in spatial population models, especially for spatially dynamic marine fish populations. We implemented a spatial simulation–estimation framework that emulated a generic marine fish metapopulation to explore the impact of ontogenetic movement and climate‐induced distributional shifts between two populations. The robustness of spatially stratified IPMs was explored across a range of movement parametrizations, including ignoring connectivity or estimating movement with various levels of complexity. Ignoring connectivity was detrimental to accurate estimation of population‐specific biomass, while implementing spatial IPMs with intermediate levels of complexity (e.g. estimating movement in two‐year and two‐age blocks) performed best when no a priori information about underlying movement was available. One‐way distributional shifts mimicking climate‐induced poleward migrations presented the greatest estimation difficulties, but the incorporation of auxiliary information on connectivity (e.g. tag‐recapture data) reduced bias. The continued development of spatially stratified modelling approaches should allow harvested resources to be better utilized without increased risk. Additionally, expanded collection and incorporation of unique spatially explicit data will enhance the robustness of IPMs in the future.

Maximising the ecological value of hard coastal structures using textured formliners

In order to enhance the ecological value of vertical hard coastal structures, hybrid designs with complex surface textures (such as a combination of grooves and pits) have been recommended. This strategy optimises ecological colonisation at two spatial scales: 1) at the mm-scale for barnacle abundance (shown to have bioprotective capabilities), and 2) at the cm-scale for species richness and abundance through the incorporation/creation of habitat features. To determine the optimal design for improving the intertidal habitat quality of vertical coastal defence structures, we conducted an ecological enhancement trial involving 160 artificial concrete tiles of different designs (and thus topographic complexity) and 24 cleared natural surfaces (150 × 150 mm) at three sites in the UK. Within 18 months, tile designs with intermediate levels of complexity (mm-scale surface roughness) were optimal in increasing barnacle cover compared to plain-cast tiles. Tiles with high complexity (with microhabitat recesses up to 30 mm deep) developed greatest species richness and mobile species abundance and had lowest peak air temperatures and highest humidity. Such textured ecological enhancements can help improve the habitat value of existing and future hard coastal structures by favouring the conservation of intertidal species in urban marine habitats and enhancing otherwise weak or absent ecosystem service provision.

Economic Complexity and Regional Growth Performance: Evidence from the Mexican Economy

This paper uses information on the productive structure of each of Mexico’s states to calculate a measure of economic complexity using the Method of Reflections proposed by Hausmann and Hidalgo (2009). The results suggest that the country’s states differ markedly in terms of the activities they specialize in, and therefore also in terms of their economic complexity. There is also a clear regional pattern which shows that states in the north are more complex, those in the central region have an intermediate level of complexity, and those in the south have the lowest levels of complexity. As previous international studies have shown, complexity is an important factor in explaining the economic disparities observed in the country, given that its measure is positively related to both the level of wealth and the growth rate of the states. Therefore, we can assert that the dispersion of productive knowledge—measured according to the specialization of the states or the location of the various economic activities performed there—goes some way toward explaining their different patterns of growth.

A Novel Algorithm for EMG Signal Processing and Muscle Timing Measurement

This paper presents a new method for the automated processing of surface electromyography (SEMG) signals, particularly suited for the detection of muscle activation timing. The method has an intermediate level of complexity between simpler (but less performing) and more complex (but in general slower) methods, and is successfully used in the development of biomedical devices for rehabilitation carried out by our group. The method proposed here is based on a statistical approach for threshold computation that is implemented without the need of maximum voluntary contraction or relaxed state, usually required to overcome the difficulty in obtaining the threshold value. The method is compared with 10 popular automated standard methods using different types of simulated signals that approximate the behavior of real SEMG signals. Both the number of activations detected and the onset time measured are analyzed. The algorithm is then applied to real SEMG signals acquired from healthy subjects. The results are finally compared with the literature values. The results show that the proposed algorithm is the best performing method when both the number of activations and the activation timing are considered. In real applications, the algorithm gives the results compatible with the well-agreed literature data.

Abstract 4977: Dramatic differences in the extents and patterns of PKC delta modification among the different members of the NCI-60 cancer cell line panel

Abstract Protein kinase Cs (PKCs) are validated targets for cancer therapy with many agents in clinical trials which affect their activity and/or expression. PKC delta is one of the most highly expressed PKC isoforms and typically functions biologically to promote apoptosis. Multiple phosphorylation sites, both on serine/threonine and on tyrosine, have been identified on PKC delta and various sites have been shown to be differentially important for the various biological activities of PKC delta. Unfortunately, phosphosite specific antibodies are only available for a few of these phosphorylation sites. Capillary isoelectric focusing on a nanoscale with immunoassay readout, using pan-reactive antibodies that detect all modified states, reveals signatures of the differently modified states of PKC delta in cells. In LNCaP cells, the phosphorylation pattern of PKC delta was modestly complex under basal conditions but it became highly complex after ligand treatment. This phosphorylation signature depended on the ligand and the subsequent subcellular localization of PKC delta. To assess the generality of the findings in the LNCaP cells, we have extended our analysis to assess the phosphorylation signatures of PKC delta in different cell lines of the NCI-60 cancer cell line panel. Under basal conditions, the various cell lines showed dramatic differences. Some of them (SR leukemia, HT-29 colon cancer, OVCAR-5 ovarian cancer, many lung cancer cell lines, T-47D breast cancer) showed a pattern similar to that of LNCaP cells. Many others (most renal cell lines, OVCAR-8 ovarian cancer, MDA-MB-468 breast cancer, SK-MEL5 melanoma) displayed a complex pattern of highly phosphorylated peaks in the PKC delta signature. The extents of PKC delta phosphorylation did not correlate with the sensitivity of the cell lines to growth inhibition by the PKC ligand mezerein. Current efforts with selected cell lines from the NCI-60 cell line panel are directed at 1) characterizing in detail the PKC delta signature using different phosphosite specific antibodies to deconvolute the modifications responsible for the multiplicity of the peaks, 2) exploring what factors influence the PKC delta signature, and 3) evaluating whether the basal PKC delta phosphorylation signature is a measure of overall DAG signaling or is specific to the PKC delta isoform. We conclude that capillary isoelectric focusing with immunoassay is a powerful tool for exploring the complexity of PKC delta activation/modification in different cells and for identifying those cancer types where dysregulation of the DAG signaling pathway is most prominent. While the current studies focus on PKC delta, this same methodology should be similarly informative for the many other proteins with an intermediate level of complexity in their post-translational modifications. Citation Format: Noemi Kedei, Jin-Qiu Chen, Michelle Herrmann, Tiffany Hu, Karina Chang, Peter M. Blumberg. Dramatic differences in the extents and patterns of PKC delta modification among the different members of the NCI-60 cancer cell line panel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4977. doi:10.1158/1538-7445.AM2015-4977

Towards an energy–landscape integrated analysis? Exploring the links between socio-metabolic disturbance and landscape ecology performance (Mallorca, Spain, 1956–2011)

The role of agricultural landscapes in biodiversity conservation is an emerging topic in a world experiencing a worrying decrease of species richness. Farm systems may either decrease or increase biological diversity, depending on land-use intensities and management. We present an intermediate disturbance-complexity model (IDC) of cultural landscapes aimed at assessing how different levels of anthropogenic disturbance on ecosystems affect the capacity to host biodiversity depending on the land matrix heterogeneity. It is applied to the Mallorca Island, amidst the Mediterranean biodiversity hotspot. The model uses the disturbance exerted when farmers alter the Net Primary Production through land-use change as well as when they remove a share of it (HANPP), together with Shannon–Wiener index (H′) of land-cover diversity. The model is tested with a twofold-scalar experimental design (1:50,000 and 1:5000) of a set of landscape units along three time points (1956, 1989, 2011). Species richness of breeding and wintering birds, taken as a biodiversity proxy, is used in an exploratory factor analysis. The results clearly show that when intermediate levels of HANPP are performed within intermediate levels of complexity (H′) in landscape patterns, like agro-forest mosaics, great bird species richness and high socio-ecological resilience can be maintained. Yet, these complex-heterogeneous landscapes are currently vanishing due to industrial farm intensification, rural abandonment and urban sprawl. The results make apparent the usefulness of transferring the concept of intermediate disturbance-complexity interplay to cultural landscapes. Our spatial-explicit IDC model can be used as a tool for strategic environmental assessment of land-use planning.

Linear and non-linear properties of feature selectivity in V4 neurons.

Extrastriate area V4 is a critical component of visual form processing in both humans and non-human primates. Previous studies have shown that the tuning properties of V4 neurons demonstrate an intermediate level of complexity that lies between the narrow band orientation and spatial frequency tuning of neurons in primary visual cortex and the highly complex object selectivity seen in inferotemporal neurons. However, the nature of feature selectivity within this cortical area is not well understood, especially in the context of natural stimuli. Specifically, little is known about how the tuning properties of V4 neurons, measured in isolation, translate to feature selectivity within natural scenes. In this study, we assessed the degree to which preferences for natural image components can readily be inferred from classical orientation and spatial frequency tuning functions. Using a psychophysically-inspired method we isolated and identified the specific visual “driving features” occurring in natural scene photographs that reliably elicited spiking activity from single V4 neurons. We then compared the measured driving features to those predicted based on the spectral receptive field (SRF), estimated from responses to narrowband sinusoidal grating stimuli. This approach provided a quantitative framework for assessing the degree to which linear feature selectivity was preserved during natural vision. First, we found evidence of both spectrally and spatially tuned suppression within the receptive field, neither of which were present in the linear SRF. Second, we found driving features that were stable during translation of the image across the receptive field (due to small fixational eye movements). The degree of translation invariance fell along a continuum, with some cells showing nearly complete invariance across the receptive field and others exhibiting little to no position invariance. This form of limited translation invariance could indicate that a subset of V4 neurons are insensitive to small fixational eye movements, supporting perceptual stability during natural vision.

Metapopulation persistence in random fragmented landscapes.

Habitat destruction and land use change are making the world in which natural populations live increasingly fragmented, often leading to local extinctions. Although local populations might undergo extinction, a metapopulation may still be viable as long as patches of suitable habitat are connected by dispersal, so that empty patches can be recolonized. Thus far, metapopulations models have either taken a mean-field approach, or have modeled empirically-based, realistic landscapes. Here we show that an intermediate level of complexity between these two extremes is to consider random landscapes, in which the patches of suitable habitat are randomly arranged in an area (or volume). Using methods borrowed from the mathematics of Random Geometric Graphs and Euclidean Random Matrices, we derive a simple, analytic criterion for the persistence of the metapopulation in random fragmented landscapes. Our results show how the density of patches, the variability in their value, the shape of the dispersal kernel, and the dimensionality of the landscape all contribute to determining the fate of the metapopulation. Using this framework, we derive sufficient conditions for the population to be spatially localized, such that spatially confined clusters of patches act as a source of dispersal for the whole landscape. Finally, we show that a regular arrangement of the patches is always detrimental for persistence, compared to the random arrangement of the patches. Given the strong parallel between metapopulation models and contact processes, our results are also applicable to models of disease spread on spatial networks.

Perception, Connotation, Translation of Numbers

<p><em>The purpose</em><em> of the note is to discuss the translation of the numbers from one language to another in order to retain their meaning (in this case it is easy) and to preserve their connotations (and this is the hard part, as in every translation). The lexical system of numbers is an excellent laboratory to study the semiotic phenomena of hypocoding and hypercoding at an intermediate level of complexity, that does not avoid the problems but still allows rigorous solutions. This problem takes a well-defined role in the two sections dedicated to perception and connotations, when some numbers assume the role of hypernyms similar to adjectives "some, many, too many". The various languages do not use the same system of hypernyms, so the translation, beyond the literal meaning, requires a particular knowledge, typical of bilingualism.</em></p>

Reading Literacy as One of the Most Significant Academic Competencies for the University Students

At the Lisbon Summit, the Council of Europe set a highly ambitious strategic goal for the European Union: to become the most competitive and dynamic knowledge-based economy in the world capable of sustainable economic growth with more and better jobs and greater social cohesion. In the process of achieving this goal, education and job readiness have played a critical role. Therefore, one of the strategic and ambitious goals is to attain the best possible quality of teaching and learning processes. One of the key academic competencies generating knowledge for the current information society is the reading literacy. The main goal of our pre-research project is to carry out a pilot study on reading literacy of the first year students at Alexander Dubcek University of Trencin, to identify their reading literacy level, and their ability to comprehend and work effectively with academic texts, and last but not least to identify their reading literacy deficiencies. The pre-research project will serve as a basis for a follow-up in-depth comparative research. In addition, suitability of the research methods will be tested and reliability and validity of the research to be carried out in collaboration with colleagues from the Universidad de Valencia and Universidad Católica de Valencia in Spain will be verified. The research on reading literacy will test Slovak and Spanish first year students studying at public and private universities. Identical texts having intermediate academic difficulty in the students’ mother tongue will be employed in order to identify and compare real competences and the reading comprehension level of university students in both countries. An empirical, analytical and comparative research will be conducted. The results we obtained in the first research phase from testing a small sample of Slovak first year university students indicated reading literacy deficiencies; i.e. students are insufficiently prepared to deal with academic texts of intermediate level of complexity and lack analytical and critical thinking. Students were assigned to write an abstract and a power-point presentation, common and frequently used linguistic genres in academic setting in order to assess their ability to systematize and synthesize written text, and thus to identify their real reading literacy.

Ecosystem models for fisheries management: finding the sweet spot

AbstractThe advent of an ecosystem‐based approach dramatically expanded the scope of fisheries management, creating a critical need for new kinds of data and quantitative approaches that could be integrated into the management system. Ecosystem models are needed to codify the relationships among drivers, pressures and resulting states, and to quantify the trade‐offs between conflicting objectives. Incorporating ecosystem considerations requires moving from the single‐species models used in stock assessments, to more complex models that include species interactions, environmental drivers and human consequences. With this increasing model complexity, model fit can improve, but parameter uncertainty increases. At intermediate levels of complexity, there is a ‘sweet spot’ at which the uncertainty in policy indicators is at a minimum. Finding the sweet spot in models requires compromises: for example, to include additional component species, the models of each species have in some cases been simplified from age‐structured to logistic or bioenergetic models. In this paper, we illuminate the characteristics, capabilities and short‐comings of the various modelling approaches being proposed for ecosystem‐based fisheries management. We identify key ecosystem needs in fisheries management and indicate which types of models can meet these needs. Ecosystem models have been playing strategic roles by providing an ecosystem context for single‐species management decisions. However, conventional stock assessments are being increasingly challenged by changing natural mortality rates and environmentally driven changes in productivity that are observed in many fish stocks. Thus, there is a need for more tactical ecosystem models that can respond dynamically to changing ecological and environmental conditions.

Comparing Perceptual and Computational Complexity for Short Rhythmic Patterns

According to Leibniz ‘Music is the hidden arithmetical exercise of a mind unconscious that it is calculating.’ The perception or experience of time is an essential aspect of listeners’ engagement with music. As such listeners’ experience of rhythmic patterns and their aesthetic response can enhance our understanding of the perception of time. Studies by Berlyne suggest that aesthetic evaluations are low for stimuli that are too simple or too complex with a preference for intermediate level of complexity. In musical terms we would expect listeners to respond negatively to music that is purely repetitive or to music that seems incomprehensibly random and to prefer music that manages to balance familiarity with variation. We present a study that aims to match listeners’ evaluation of rhythmic complexity with computational measures of complexity. We selected five measures derived from information theory - Shannon's entropy, entropy rate, excess entropy, transient information, and Kolmogorov complexity. Rhythmic sequences, covering a wide spectrum of complexity levels according to these measures, were generated algorithmically as binary sequences. These sequences were synthesized as drum patterns with 1s as hits and 0s as rests. 32 participants were asked to guess whether the last beat of each sequence was supposed to be a drum hit or a rest. We averaged the participants’ scores in order to assign an implicit rating of rhythm complexity to each sequence. We also obtained an explicit rating of complexity by asking the participants to rate the perceived difficulty of guessing the last beat for each sequence. Finally, the participants completed the Gold-MSI questionnaire and a shortened version of the Raven's matrices, in order to investigate the effects of musicality and visual pattern identification on the perception of rhythm complexity. The Kolmogorov complexity of the sequences was correlated with the scores on the explicit task (r=.973, p<.001), and the entropy rate of the sequences was correlated with the scores on both implicit (r=.670, p=.012) and explicit tasks (r=.909, p<.001). There was also a Kolmogorov complexity-by-musicality interaction (F=5.498, p=.026), confirming the influence of musical expertise in the perception of rhythm complexity. There was no effect of the scores on the Raven's matrices, showing that auditory sequence perception and visual pattern identification seem to be different abilities. These results show that information-theoretical concepts capture some salient features of rhythm perception, and provide the framework for further studies on the aesthetic perception of rhythm.